Ive had the same issue. When I brought my BP home in November he w as at 215 grams. I found a shop that carries live rat pups. After the first two feedings they have no longer had them. I then fed a small rat which weighed about 36 grams. He took it no problem. After that third feeding I weighed him and he was 255 grams. Next feeding was a F/T pup which he took then the next three weeks he wouldn't take F/T. So today I got another small rat that appeared to be in the 35-40 gram range and he took it no problem. Even though they are larger then what the chats show he should be eating the small rats are just about as big around as his midsection so I feel they are OK. I am hoping to get him switched to F/T so I can better regulate the sizes I get him. I would guess that the small/weened rats will be fine.